The Teide-Pico Viejo (T-PV) stratovolcanoes constitute one of the most potentially active volcanic complexes in Europe. T-PV was traditionally considered as a non-explosive system, but recent studies have pointed out the explosive character of their phonolitic magmas, including plinian and subplinian eruptions and the generation of pyroclastic density currents, as is evidenced in the volcanological record of the last 30 kyr. This explosive activity is mostly associated with satellite dome-like vents, which are characterised by presenting progressive transitions between explosive and effusive activity. In order to improve our understanding of these types of eruptions and their controlling mechanisms, we conducted a petrological and mineral characterisation of the products from the different eruptive phases of Pico Cabras dome. This permitted us to constrain the pre-eruptive conditions of the magma and to infer the potential factors that control the changes in the volcanic activity of dome-forming eruptions at T-PV and, in particular, the transition between explosive and effusive phases.

Feldspar (anorthoclase and sanidine), clinopyroxene (diopside and augite), biotite, amphibole (kaersutite), magnetite, ilmenite, sodalite, and glass samples were analysed using EPMA and Micro-XRF. Our results suggest the presence of a compositionally, thermally, and volatile stratified magma chamber at 100 ± 50 MPa prior to the Pico Cabras eruption (between 9210 and 5911 years BP), which was characterised by a progressive change in the style of activity, from an efficiently fragmented magma dispersed by a sustained plume, to a poorly-fragmented, low-height, non-convective fountain (forming the fountain-fed lava dome) to a glass-bearing lava flow activity. The transition in the eruptive style was controlled by changes in temperature and amount of volatiles dissolved in the phonolitic melt (i.e., differences in magma rheology). The initial explosive phase was related to the emission of highly evolved phonolitic magma ponding at 725–825 °C while containing 3.5–5 wt% H₂O and located in the upper part of the magma reservoir. The magma that fed the phonolitic lava flow formed the main body of the reservoir and was stored below the preceding melt at 880 ± 30 °C and with 2.5–3 wt% H₂O dissolved. Feldspar zonation suggests that the eruption was triggered by the intrusion of hotter mafic magma at the base of the phonolitic chamber, which induced the overturn of the interior of the reservoir. However, the interaction between the internal magmas was short enough to prevent the hybridization phenomena among them. The compositions of some feldspars from the most explosive phase are equivalent to those found in the El Abrigo eruption, the last caldera-forming episode (ca. 190 ka), demonstrating that T-PV volcanic system can already produce evolved and highly explosive magmas, a factor that should be considered in future hazard assessment for Tenerife.

泰德-皮科维约（T-PV）平流层火山是欧洲最有潜力的火山复合体之一。T-PV通常被认为是非爆炸性系统，但是最近的研究指出了它们的胶状岩浆的爆炸特性，包括including系和亚p系喷发以及火山碎屑密度流的产生，这在最近的火山学记录中得到了证明。 30吉尔。这种爆炸性活动主要与卫星圆顶状通风口有关，其特征是在爆炸性活动与喷发性活动之间呈现渐进过渡。为了增进对这些喷发类型及其控制机制的理解，我们对来自Pico Cabras穹顶不同喷发阶段的产品进行了岩石学和矿物学表征。

使用EPMA和Micro-XRF分析了长石（正长石和山梨酸），斜辉石（透辉石和辉石），黑云母，闪石（角铁矿），磁铁矿，钛铁矿，方钠石和玻璃样品。我们的结果表明，在Pico Cabras喷发之前（9210至5911年BP之间），在100±50 MPa时存在成分，热和挥发性的分层岩浆腔，其特征是活动方式逐渐发生变化。由持续的羽流散布的有效破碎的岩浆，到破碎程度低，低高度，非对流的喷泉（形成由喷泉注入的熔岩穹顶），形成带有玻璃的熔岩流活动。喷发型的转变是由温度和溶在胶质熔体中的挥发物的量（即岩浆流变学差异）控制的。₂ O，位于岩浆储层的上部。注入火山岩熔岩流的岩浆形成了储层的主体，并以880±30°C和2.5–3 wt％的H ₂储存在先前的熔体下方。O溶解。长石的带状化表明火山喷发是由较热的铁镁质岩浆侵入到音室的底部而引起的，它引起了储层内部的倾覆。但是，内部岩浆之间的相互作用足够短，以防止它们之间发生杂交现象。爆炸性最强的某些长石的成分与末次火山口形成事件（约190 ka）的El Abrigo火山喷发中的成分相同，这表明T-PV火山系统已经可以产生演化且高度爆炸性的岩浆，特内里费岛的未来危害评估中应考虑的因素。